The present invention broadly relates to material transport or conveyance apparatuses for handling various types of piece goods or products, and, in particular, relates to a new and improved construction of an endless revolving transport apparatus for piece goods, especially for printed products.
Generally speaking, the endless revolving piece good-transport apparatus of the present development is of the type comprising a number of entrainment elements which revolve or circulate in a guide device and which are coupled with one another or intercoupled by means of drag connections. These entrainment elements move through a conveying-active path having a starting region and a terminal region. At such starting region and at the terminal region of the conveying-active path of the entrainment elements, the latter are driven by a respective controllable drive device. The entrainment elements can be positioned as concerns their mutual orientation or disposition with respect to one another in order to regulate the product taken-over cadence or rate and the product outfeed or delivery cadence or rate independent of one another.
Such type of transport apparatus has become known in this technology, for instance, from Swiss Pat. No. 610,276, granted Apr. 12, 1979 and the cognate U.S. Pat. No. 4,072,228, granted Feb. 7, 1978. The entrainment elements of this transport apparatus possess undercarriages having wheels which are guided in pairs in U-shaped rails which are arranged such that their open sides or openings confront one another. At the front and rear end walls of the undercarriages, there are provided openings through which extend connection elements. These connection elements carry hooks at their opposed ends. These hooks engage about impact ledges provided at the end walls of the undercarriages. At the central region between the hooks, there are arranged buffers or shock absorbers at the connection elements. The drive of the entrainment elements is accomplished by means of worms which, at the starting region and at the terminal or end region of the conveying-active path of the transport apparatus, act upon follower rolls which are arranged at the undercarriages. The drive velocity of the first worm is governed by the infeed clock rate or cadence of the arriving printed products and the drive velocity of the second worm is governed by the clock rate or cadence for further processing of the printed products. The difference between the product conveying velocities at the starting region and at the terminal region of the conveying-active path of the transport apparatus is compensated by the drag connection. This can result in noisy travel of the entrainment elements because the acceleration and deceleration of the undercarriages occurs suddenly due to the impact or contact with the hooks or shock absorbers, as the case may be.